1. Field of the Invention
One or more embodiments of the present application relate to copper sulfate, a copper sulfate solution, a plating solution, a method for producing copper sulfate, method for producing a semiconductor circuit board, and a method for producing an electronic apparatus.
2. Description of the Related Art
Copper sulfate has been widely used as raw materials for an electrolytic solution, a pigment, an insecticide, an antiseptic, a mordant, a material for battery cells, a medical drug, an electroplating solution for electronic components, such as a semiconductor device, and the like.
For example, as copper sulfate capable of being applied to raw materials for an electrolytic solution, a pigment, an insecticide, an antiseptic, a mordant, a material for battery cells, a medical drug, an electroplating solution for electronic components, such as a semiconductor device, and the like, Japanese Patent No. 3,987,069 describes high purity copper sulfate having a purity of 99.99% by weight or more and a content of transition metals, such as Fe, Cr, and Ni, of 3 ppm by weight or less. Japanese Patent No. 3,943,583 describes high purity copper sulfate having a purity of 99.999% by weight or more.
However, according to the various demands in recent years, there is an increasing demand of copper sulfate having a further reduced impurity content, as compared to the high purity copper sulfate described in Japanese Patent Nos. 3,987,069 and 3,943,583.
For example, in the case where copper sulfate is used as a raw material of a copper plating bath, there is a problem that associated to the miniaturization of wiring, iron contained copper sulfate as a raw material for a copper plating bath decreases the conductivity of the copper film.
One or more embodiments of the present application provide copper sulfate having a reduced iron concentration, a copper sulfate solution, a plating solution, a method for producing copper sulfate, a method for producing a semiconductor circuit board, and a method for producing an electronic apparatus.